My wife is using Google Photos, and I've been using Photoprism for a few months. I just had a baby, and I access to download the pictures that my wife takes.
I'm not too sure of what I want. I guess I want two separate libraries, but I want to be able to view her pictures easily and add them into my library.
I believe if I spin up a second photoprism instance, I'd have to download her pictures individually and reupload them into my instance.
What do any of you do? Do you even host photo storage for your family?
Tagging onto this: Does anyone know of the easiest way to backfill Immich with photos from Google photos all at once besides manually downloading them from the Photos site?
I used rclone to get all my photos down, then I used Immich’s bulk import API to get everything into Immich just yesterday. I did about 14k photos.
Take note of the limitations of rclone though, it won’t get the original full resolution - https://rclone.org/googlephotos/#limitations you need to use Google Takeout to get full resolution.
To add onto this, has anyone found a good way to combine the metadata back into the photos from Google takeout? I've found two solutions on Google, one was send it off to some company and pay them to do it and the other has me run some pre compiled exe file. 
I'm starting to think I'll just have to live without the metadata or write my own solution.
For your use case I would definitely recommend Immich. It has a "partner sharing" feature that allows you to view your partners photos from your account while still maintaining separate archives. You can then download or add to albums from there. Immich has been fantastic for my family because it supports android and iOS (being as I can't get some members off Apple products.)
Here's the description of the feature. Sorry it's a Reddit post, that's the only place I could find the developers summary of the update.
I don't use it for my photos because of the UI but the update process has been rock solid for the last couple of years since I moved and started uaing their snap. It updates itself automatically withot any of my interaction and never breaks.
Using bare metal install? I always cried when I had to apply updates, but now that I moved on the docker image , I don't get problems when updating (knocking wood)
omg I didn't know if it was just me but I have the worst luck with Nextcloud updates. I've had to restore from backup like 6 times in the 4 years that I've been running an instance.
With a very small library it's fine using the "memories" app, but I noticed in my experiments that adding thousands of pictures is a miserable experience
I was looking for something better than sharing pictures four at a time on Mastodon and checked out Pixelfed. I don't understand it at all. It's like the system is designed around sharing individual pictures. Even when an instance allows sharing a few pictures at once, other users will only see the first picture because multiple pictures is obviously an afterthought for the UI. Maybe it's because I am too old and I want Flickr instead of Instagram. I'm still posting pictures up to four at a time on Mastodon.
Google photos does this. You can enable partner sharing where you can see all of their photos. You can choose to save them all by default, or selectively save them.